MULTI-DIMENSIONAL NMR OF HIV-1 ENVELOPE GLYCOPROTEINS

HIV-1 包膜糖蛋白的多维核磁共振

• 批准号: 6944342
• 负责人: JACOB ANGLISTER
• 金额: $ 18.9万
• 依托单位: WEIZMANN INSTITUTE OF SCIENCE
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-01 至 2007-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6944342
• 关键词: HIV envelope protein gp41; antigen antibody reaction; antiviral antibody; chemokine receptor; conformation; fluorescence spectrometry; human immunodeficiency virus 1; nuclear magnetic resonance spectroscopy; peptide structure; protein structure; protein structure function; receptor binding; synthetic peptide

DESCRIPTION (provided by applicant): The long-range goal of our research is to understand the mechanism for co-receptor selectivity by HIV-1 (binding to CCR5 and CXR4 receptors) and the role of the membrane proximal domain of the envelope glycoprotein gp41 in HIV-1 fusion. The binding of HIV-1 and its fusion to target cells is mediated by the gp120 and gp41 envelope glycoproteins of the virus. The third variable loop (V3) of gp120 is a major neutralizing determinant of HIV-I. Segments of V3 form the binding site for the gp120 co-receptors on T-cells and macrophages and its sequence determines the virus phenotype, i.e. whether it binds the CCR5 chemokine receptor and infects macrophages (designated R5 virus), or it binds CXCR4 and infects T-cells (designated X4 virus). Deletion of V3 or its binding to antibodies prevents HIV-1 fusion with its target cells, thus abolishing its infectivity. We suggest that the selectivity of HIV-1 is determined to a major extent by alternative conformations of V3. The binding of gp120 to the chemokine receptors induces conformational changes in gp41 that mediate viral fusion with the target cell. The tryptophan-rich C-terminal membrane proximal domain of gp41 contains the only neutralizing epitope within gp41, and partially overlaps with the sequence of the peptide DP178, a strong entry-inhibitor of HIV-1 under clinical trials. Given the important biological properties and lack of complete structural information on gp120 and gp41, multi-dimensional NMR techniques will be used to decipher the missing structures of key components of these envelope proteins, as free peptides, constrained peptide analogs, when bound to broadly neutralizing anti-HIV-1 antibodies, and in the context of the gp41 protein. The structure of the alternative conformation of V3 recognized by HIV-1 neutralizing antibodies will be determined. Constrained peptides mimicking these conformations will be synthesized and their structure determined. The characterization of CCR5 and CXCR4 selectivity to the constrained conformations will have profound implications on our understanding of the mechanism for co-receptor selectivity and HIV-1 neutralization by antibodies directed against the V3 loop. The structure of the N- and C-terminal regions of gp41 extra-cellular domain will shed light on their involvement in membrane fusion, and the importance of the C-terminal half of DP178 for antiviral activity and for eliciting neutralizing antibodies. This study will provide invaluable information for constructing immunogens for HIV-1 vaccines and for developing anti-HIV-1 therapeutics.

描述(由申请人提供)： 我们研究的长期目标是了解HIV-1(与CCR5和CXR4受体结合)选择性共受体的机制，以及包膜糖蛋白gp41的膜近端结构域在HIV-1融合中的作用。HIV-1及其融合与靶细胞的结合是由病毒的gp120和gp41包膜糖蛋白介导的。Gp120的第三个可变环(V3)是HIV-I的主要中和决定因素。V3的片段形成T细胞和巨噬细胞上gp120辅助受体的结合部位，其序列决定了病毒的表型，即它是与CCR5趋化因子受体结合并感染巨噬细胞(命名为R5病毒)，还是与CXCR4结合并感染T细胞(命名为X4病毒)。V3的缺失或其与抗体的结合阻止了HIV-1与其目标细胞的融合，从而消除了它的传染性。我们认为HIV-1的选择性在很大程度上是由V3的替代构象决定的。Gp120与趋化因子受体的结合诱导gp41的构象变化，从而介导病毒与靶细胞的融合。Gp41富含色氨酸的C端膜近端区域含有gp41内唯一的中和表位，并与正在临床试验中的HIV-1的强进入抑制因子DP178的序列部分重叠。鉴于gp120和gp41的重要生物学特性和缺乏完整的结构信息，多维核磁共振技术将被用于破译这些包膜蛋白关键成分的缺失结构，当与广泛中和的抗HIV-1抗体结合时，作为游离肽、受限制的肽类似物，以及在gp41蛋白的背景下。将确定HIV-1中和抗体识别的V3替代构象的结构。模拟这些构象的限制性多肽将被合成并确定它们的结构。CCR5和CXCR4对限制性构象的选择性的表征将对我们理解针对V3环的抗体的辅助受体选择性和HIV-1中和机制有深远的影响。Gp41胞外区N-末端和C-末端区域的结构将揭示它们参与膜融合的过程，以及DP178的C-末端半部分对于抗病毒活性和诱导中和抗体的重要性。这项研究将为构建HIV-1疫苗的免疫原和开发抗HIV-1治疗药物提供宝贵的信息。